platform_system_core/libcutils/klog.c

79 lines
2.0 KiB
C

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <cutils/klog.h>
static int klog_fd = -1;
static int klog_level = KLOG_DEFAULT_LEVEL;
int klog_get_level(void) {
return klog_level;
}
void klog_set_level(int level) {
klog_level = level;
}
void klog_init(void) {
if (klog_fd >= 0) return; /* Already initialized */
klog_fd = open("/dev/kmsg", O_WRONLY | O_CLOEXEC);
if (klog_fd >= 0) {
return;
}
static const char* name = "/dev/__kmsg__";
if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
klog_fd = open(name, O_WRONLY | O_CLOEXEC);
unlink(name);
}
}
#define LOG_BUF_MAX 512
void klog_writev(int level, const struct iovec* iov, int iov_count) {
if (level > klog_level) return;
if (klog_fd < 0) klog_init();
if (klog_fd < 0) return;
TEMP_FAILURE_RETRY(writev(klog_fd, iov, iov_count));
}
void klog_write(int level, const char* fmt, ...) {
if (level > klog_level) return;
char buf[LOG_BUF_MAX];
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
buf[LOG_BUF_MAX - 1] = 0;
struct iovec iov[1];
iov[0].iov_base = buf;
iov[0].iov_len = strlen(buf);
klog_writev(level, iov, 1);
}